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Personal homepage of Dr. Jan Wilhelm


Research

Ultrafast dynamics in quantum materials

Absorption and emission of light visualized in the bandstructure of Dirac fermions.

When irradiating solids with a laser pulse of frequency $\omega$, the corresponding electric field initiates ultrafast electron dynamics in the material. Fingerprints of the ultrafast dynamics are encoded in the emission spectrum that features high-harmonic frequencies $n\omega,n\in\mathbb{N}$. We simulate ultrafast electron dynamics and high-harmonic generation to explore exciting physics in exotic materials as topological insulators. For simulations, we employ our open-source software package CUED.

Publication reference: [18]



Low-scaling many-body perturbation theory

'GW meter': Computational cost of GW can be reduced from $O(N^4)$ to $O(N^2)$.

GW is the state-of-the-art method to compute band structures of solids and electronic levels in molecules. Today's largest supercomputers are required, when applying GW to systems with more than hundred atoms. We work on a low-scaling GW algorithm to enable GW for thousands of atoms. Our developments are implemented in the open-source package CP2K.

Publication references: [10], [19]

Teaching

SS 2021: Computational Nanoscience (lecture and exercises)
SS 2020: Computational Nanoscience (lecture and exercises)
WS 2019/2020: Integrated Course II: Statistical Physics and Solid State Physics (exercises)

Short CV

12/2019 - present: Akademischer Rat (lecturer), University of Regensburg
2017 - 2019: Research Scientist, BASF, Ludwigshafen
2014 - 2017: PhD in Theoretical Chemistry (with Prof. J. Hutter), University of Zurich
2009 - 2016: Studies of Physics and Mathematics, Karlsruhe Institute of Technology

Publications

The publication list is also available on Google Scholar.
  1. J. Wilhelm, P. Seewald, D. Golze: Low-scaling GW with benchmark accuracy and application to phosphorene nanosheets, J. Chem. Theory Comput. 17, 1662-1677 (2021).
  2. J. Wilhelm, P. Grössing, A. Seith, J. Crewse, M. Nitsch, L. Weigl, C. Schmid, F. Evers: Semiconductor Bloch-equations formalism: Derivation and application to high-harmonic generation from Dirac fermions, Phys. Rev. B 103, 125419 (2021).
  3. T. D. Kühne, M. Iannuzzi, M. Del Ben, V. V. Rybkin, P. Seewald, F. Stein, T. Laino, R. Z. Khaliullin, O. Schütt, F. Schiffmann, D. Golze, J. Wilhelm, S. Chulkov, M. H. Bani-Hashemian, V. Weber, U. Borstnik, M. Taillefumier, A. S. Jakobovits, A. Lazzaro, H. Pabst, T. Müller, R. Schade, M. Guidon, S. Andermatt, N. Holmberg, G. K. Schenter, A. Hehn, A. Bussy, F. Belleflamme, G. Tabacchi, A. Glöß, M. Lass, I. Bethune, C. J. Mundy, C. Plessl, M. Watkins, J. VandeVondele, M. Krack, J. Hutter: CP2K: An electronic structure and molecular dynamics software package - Quickstep: Efficient and accurate electronic structure calculations, J. Chem. Phys. 152, 194103 (2020).
  4. T. T. Duignan, G. K. Schenter, J. L. Fulton, T. Huthwelker, M. Balasubramanian, M. Galib, M. D. Baer, J. Wilhelm, J. Hutter, M. Del Ben, X. S. Zhao, C. J. Mundy: Quantifying the hydration structure of sodium and potassium ions: taking additional steps on Jacob’s Ladder, Phys. Chem. Chem. Phys. 22, 10641-10652 (2020).
  5. J. I. Urgel, S. Mishra, H. Hayashi, J. Wilhelm, C. A. Pignedoli, M. Di Giovannantonio, R. Widmer, M. Yamashita, N. Hieda, P. Ruffieux, H. Yamada, R. Fasel: On-surface light-induced generation of higher acenes and elucidation of their open-shell character, Nat. Commun. 10, 861 (2019).
  6. D. Beyer, S. Wang, C. A. Pignedoli, J. Melidonie, B. Yuan, C. Li, J. Wilhelm, P. Ruffieux, R. Berger, K. Müllen, R. Fasel, X. Feng: Graphene Nanoribbons Derived From Zigzag Edge-Encased Poly (para-2, 9-dibenzo [bc, kl] coronenylene) Polymer Chains, J. Am. Chem. Soc. 141, 2843-2846 (2019).
  7. J. Wilhelm, J. VandeVondele, V. V. Rybkin: Dynamics of the Bulk Hydrated Electron from Many‐Body Wave‐Function Theory, Angew. Chem. Int. Ed. 58, 3890-3893 (2019).
  8. D. Golze, J. Wilhelm, M. J. van Setten, P. Rinke: Core-level binding energies from GW: An efficient full-frequency approach within a localized basis, J. Chem. Theory Comput. 14, 4856-4869 (2018).
  9. M. Di Giovannantonio, J. I. Urgel, U. Beser, A. V. Yakutovich, J. Wilhelm, C. A. Pignedoli, P. Ruffieux, A. Narita, K. Müllen, R. Fasel: On-Surface Synthesis of Indenofluorene Polymers by Oxidative Five-Membered Ring Formation, J. Am. Chem. Soc. 140, 3532-3536 (2018).
  10. J. Wilhelm, D. Golze, L. Talirz, J. Hutter, C. A. Pignedoli: Toward GW calculations on thousands of atoms, J. Phys. Chem. Lett. 9, 306-312 (2018).
  11. J. Wilhelm, J. Hutter: Periodic GW calculations in the Gaussian and plane-waves scheme, Phys. Rev. B 95, 235123 (2017).
  12. D. Golze, N. Benedikter, M. Iannuzzi, J. Wilhelm, J. Hutter: Fast evaluation of solid harmonic Gaussian integrals for local resolution-of-the-identity methods and range-separated hybrid functionals, J. Chem. Phys. 146, 034105 (2017).
  13. J. Wilhelm, P. Seewald, M. Del Ben, J. Hutter: Large-scale cubic-scaling random phase approximation correlation energy calculations using a Gaussian basis, J. Chem. Theory Comput. 12, 5851-5859 (2016).
  14. J. Wilhelm, M. Del Ben, J. Hutter: GW in the Gaussian and plane waves scheme with application to linear acenes, J. Chem. Theory Comput. 12, 3623-3635 (2016).
  15. J. Wilhelm, M. Walz, F. Evers: Ab initio spin-flip conductance of hydrogenated graphene nanoribbons: Spin-orbit interaction and scattering with local impurity spins, Phys. Rev. B 92, 014405 (2015).
  16. M. Walz, J. Wilhelm, F. Evers: Current patterns and orbital magnetism in mesoscopic dc transport, Phys. Rev. Lett. 113, 136602 (2014).
  17. J. Wilhelm, M. Walz, F. Evers: Ab initio quantum transport through armchair graphene nanoribbons: Streamlines in the current density, Phys. Rev. B 89, 195406 (2014).
  18. N. Bajales, S. Schmaus, T. Miyamashi, W. Wulfhekel, J. Wilhelm, M. Walz, M. Stendel, A. Bagrets, F. Evers, S. Ulas, B. Kern, A. Böttcher, M. M. Kappes: C58 on Au (111): A scanning tunneling microscopy study, J. Chem. Phys. 138, 104703 (2013).
  19. J. Wilhelm, M. Walz, M. Stendel, A. Bagrets, F. Evers: Ab initio simulations of scanning-tunneling-microscope images with embedding techniques and application to C58-dimers on Au(111), Phys. Chem. Chem. Phys. 15, 6684-6690 (2013).

Book

Stoffumwandlungen und Bilanzen: Ein Lehrbuch für Wirtschaftsingenieure, 2012/2013
(in German; book for Industrial Engineering students at KIT to prepare for Chemical Engineering exam; passing the exam was mandatory until 2015 to obtain B.Sc. degree in Industrial Engineering; ISBN: 978-3000431555)


Contact
Email: jan.wilhelm(at)ur.de
Phone: +49 (0) 941 943 2040
Office: PHY 3.1.24

Address
Institute of Theoretical Physics
Universitätsstraße 31
D-93053 Regensburg

 
Last modified: 10th Jun, 2021 by Jan Wilhelm